• Nutrition Research and Practice
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• v.17 no.2
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• pp.257-268
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• 2023

BACKGROUND/OBJECTIVES: Zinc is an essential trace mineral which is important for the growth and development of the human body and immunological and neurological functions. Inadequate zinc intake may cause zinc deficiency with its adverse consequences. In this study, we aimed to estimate the dietary zinc intake levels and sources among Koreans. SUBJECTS/METHODS: For this secondary analysis, we obtained data from the Korea National Health and Nutrition Examination Survey (KNHANES) 2016-2019. Individuals aged ≥ 1 yr who had completed a 24-h recall were included. The dietary zinc intake of each individual was calculated by applying data from a newly developed zinc content database to the KNHANES raw data. We also compared the extracted data with the sex-, age-specific reference values suggested in the Korean Dietary Reference Intakes 2020. The prevalence of adequate zinc intake was then evaluated by the proportion of the individuals who met the estimated average requirement (EAR). RESULTS: The mean zinc intake of Koreans aged ≥ 1 yr and adults aged ≥ 19 yrs were 10.2 and 10.4 mg/day, equivalent to 147.4% and 140.8% of the EAR, respectively. Approximately 2 in 3 Koreans met the EAR for zinc, but the zinc intake differed slightly among the different age and sex groups. In children aged 1-2 yrs, 2 out of 5 exceeded the upper level of intake, and nearly half of the younger adults (19-29 yrs) and the elders (≥ 75 yrs) did not meet the EAR. The major contributing food groups were grains (38.9%), meats (20.4%), and vegetables (11.1%). The top 5 food contributors to zinc intake were rice, beef, pork, egg, and baechu kimchi, which accounted for half of the dietary intake. CONCLUSION: The mean zinc intake among Koreans was above the recommended level, but 1 in 3 Koreans had inadequate zinc intake and some children were at risk of excessive zinc intake. Our study included zinc intake from diet only, thus to better understand zinc status, further research to include intake from dietary supplements is needed.

• Journal of Animal Science and Technology
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• v.47 no.6
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• pp.963-974
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• 2005

This study was conducted to examine the growth performance, carcass characteristics, physico-chemical properties and fatty acid composition of muscle tissues of Hanwoo steers when they were fed diets containing four levels of E. ulmoides leaves. Steers were allotted to one of four dietary treatments, which were designed to progressively substitute Eucommia ulmoides for 0, 3, 5 and 10% of the rice straw in the basal diet. Seventy two Hanwoo steers (321±13kg) were used. Average daily gain (0.81-0.86kg) and feed conversion (10.05-10.59) were not changed by feeding E. ulmoides leaves. Emission of fecal ammonia gas was decreased by increasing substitution levels of E. ulmoides leaves. Emission of ammonia gas in feces of steers were significantly (p<0.05) decreased in the 5% and 10% treatments at 40℃ compared with in control (30.6ppm) and 3% treatment (29.8ppm), respectively 20.3 and 21.6ppm. Back fat thickness was higher (p<0.05) in steers fed control diet (15.0mm) than 5 and 10% E. ulmoides diets (10.2 and 10.5mm respectively). The grade ‘A’ appearances of meat yield of steers were increased up to 20% by the 3% substitution of E. ulmoides leaves, and the grades ‘1+’ and ‘1’ appearances of meat quality were significantly improved (p<0.05) by the 5 and 10% Eucommia ulmoides feeding. There was no statistical difference in meat color of loin and top round among all treatments. It appeared that the 5% and 10% E. ulmoides leaves feeding affected (p<0.05) a increase in oleic acid concentration in loin and top round muscles. The concentration of serum cholesterol was lower (p<0.05) in steers fed 10% E. ulmoides (53.3mg/100g) than that of the other treatments (55.7-57.0mg/100g). The diarrhea incidence was about 20.26% in control, while it was lower (p<0.05) in the 5 and 10% E. ulmoides leaves treatments (10.4-12.5%) than control. There was no statistical difference in the occurrences of respiratory disease among all treatments. It is concluded that E. ulmoides leaves should be a prospective feed additive because it contains various functional substances. It is likely that air-dried E. ulmoides leaves can reduce the back fat thickness of Hanwoo steers and the occurrences of diarrhea. Therefore, the 5 and 10% substitution of E. ulmoides for roughage are highly recommended to be used in practice.

• Journal of Biosystems Engineering
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• v.4 no.2
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• pp.65-83
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• 1979

Low-temperature drying systems have been extensively used for drying cereal grain such as shelled corn and wheat. Since the 1973 energy crisis, many researches have been conducted to apply solar energy as supplemental heat to natural air drying systems. However, little research on rough rice drying has been done in this area, especially very little in Korea. In designing a solar drying system, quality loss, airflow requirements, temperature rise of drying air, fan power and energy requirements should be throughly studied. The factors affecting solar drying systems are airflow rate, initial moisture content, the amount of heat added to drying air, fan operation method and the weather conditions. The major objectives of this study were to analyze the effects of the performance factors and determine design parameters such as airflow requirements, optimum bed depth, optimum temperature rise of drying air, fan operation method and collector size. Three hourly observations based on the 4-year weather data in Chuncheon area were used to simulate rough rice drying. The results can be summarized as follows: 1. The results of the statistical analysis indicated that the experimental and predicted values of the temperature rise of the air passing through the collector agreed well. 2. Equilibrium moisture content was affected a little by airflow rate, but affected mainly by the amount of heat added, to drying air. Equilibrium moisture content ranged from 12.2 to 13.2 percent wet basis for the continuous fan operation, from 10.4 to 11.7 percent wet basis for the intermittent fan operation respectively, in range of 1. 6 to 5. 9 degrees Centigrade average temperature rise of drying air. 3. Average moisture content when top layer was dried to 15 percent wet basis ranged from 13.1 to 13.9 percent wet basis for the continuous fan operation, from 11.9 to 13.4 percent wet basis for the intermittent fan operation respectively, in the range of 1.6 to 5.9 degrees Centigrade average temperature rise of drying air and 18 to 24 percent wet basis initial moisture content. The results indicated that grain was overdried with the intermittent fan operation in any range of temperature rise of drying air. Therefore, the continuous fan operation is usually more effective than the intermittent fan operation considering the overdrying. 4. For the continuous fan operation, the average temperature rise of drying air may be limited to 2.2 to 3. 3 degrees Centigrade considering safe storage moisture level of 13.5 to 14 perceut wet basis. 5. Required drying time decrease ranged from 40 to 50 percent each time the airflow rate was doubled and from 3.9 to 4.3 percent approximately for each one degrees Centigrade in average temperature rise of drying air regardless of the fan operation methods. Therefore, the average temperature rise of drying air had a little effect on required drying time. 6. Required drying time increase ranged from 18 to 30 percent approximately for each 2 percent increase in initial moisture content regardless of the fan operation methods, in the range of 18 to 24 percent moisture. 7. The intermittent fan operation showed about 36 to 42 percent decrease in required drying time as compared with the continuous fan operation. 8. Drymatter loss decrease ranged from 34 to 46 percent each time the airflow rate was doubled and from 2 to 3 percent approximately for each one degrees Centigrade in average temperature rise of drying air, regardless of the fan operation methods. Therefore, the average temperature rise of drying air had a little effect on drymatter loss. 9. Drymatter loss increase ranged from 50 to 78 percent approximately for each 2 percent increase in initial moisture content, in the range of 18 to 24 percent moisture. 10. The intermittent fan operation: showed about 40 to 50 percent increase in drymatter loss as compared with the continuous fan operation and the increasing rate was higher at high level of initial moisture and average temperature rise. 11. Year-to-year weather conditions had a little effect on required drying time and drymatter loss. 12. The equations for estimating time required to dry top layer to 16 and 1536 wet basis and drymatter loss were derived as functions of the performance factors. by the least square method. 13. Minimum airflow rates based on 0.5 percent drymatter loss were estimated. Minimum airflow rates for the intermittent fan operation were approximately 1.5 to 1.8 times as much as compared with the continuous fan operation, but a few differences among year-to-year. 14. Required fan horsepower and energy for the intermittent fan operation were 3. 7 and 1. 5 times respectively as much as compared with the continuous fan operation. 15. The continuous fan operation may be more effective than the intermittent fan operation considering overdrying, fan horsepower requirements, and energy use. 16. A method for estimating the required collection area of flat-plate solar collector using average temperature rise and airflow rate was presented.

• Journal of Biosystems Engineering
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• v.4 no.2
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• pp.64-64
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• 1979

Low-temperature drying systems have been extensively used for drying cereal grain such as shelled corn and wheat. Since the 1973 energy crisis, many researches have been conducted to apply solar energy as supplemental heat to natural air drying systems. However, little research on rough rice drying has been done in this area, especially very little in Korea. In designing a solar drying system, quality loss, airflow requirements, temperature rise of drying air, fan power and energy requirements should be throughly studied. The factors affecting solar drying systems are airflow rate, initial moisture content, the amount of heat added to drying air, fan operation method and the weather conditions. The major objectives of this study were to analyze the effects of the performance factors and determine design parameters such as airflow requirements, optimum bed depth, optimum temperature rise of drying air, fan operation method and collector size. Three hourly observations based on the 4-year weather data in Chuncheon area were used to simulate rough rice drying. The results can be summarized as follows: 1. The results of the statistical analysis indicated that the experimental and predicted values of the temperature rise of the air passing through the collector agreed well.2. Equilibrium moisture content was affected a little by airflow rate, but affected mainly by the amount of heat added, to drying air. Equilibrium moisture content ranged from 12.2 to 13.2 percent wet basis for the continuous fan operation, from 10.4 to 11.7 percent wet basis for the intermittent fan operation respectively, in range of 1. 6 to 5. 9 degrees Centigrade average temperature rise of drying air.3. Average moisture content when top layer was dried to 15 percent wet basis ranged from 13.1 to 13.9 percent wet basis for the continuous fan operation, from 11.9 to 13.4 percent wet basis for the intermittent fan operation respectively, in the range of 1.6 to 5.9 degrees Centigrade average temperature rise of drying air and 18 to 24 percent wet basis initial moisture content. The results indicated that grain was overdried with the intermittent fan operation in any range of temperature rise of drying air. Therefore, the continuous fan operation is usually more effective than the intermittent fan operation considering the overdrying.4. For the continuous fan operation, the average temperature rise of drying air may be limited to 2.2 to 3. 3 degrees Centigrade considering safe storage moisture level of 13.5 to 14 perceut wet basis.5. Required drying time decrease ranged from 40 to 50 percent each time the airflow rate was doubled and from 3.9 to 4.3 percent approximately for each one degrees Centigrade in average temperature rise of drying air regardless of the fan operation methods. Therefore, the average temperature rise of drying air had a little effect on required drying time.6. Required drying time increase ranged from 18 to 30 percent approximately for each 2 percent increase in initial moisture content regardless of the fan operation methods, in the range of 18 to 24 percent moisture.7. The intermittent fan operation showed about 36 to 42 percent decrease in required drying time as compared with the continuous fan operation.8. Drymatter loss decrease ranged from 34 to 46 percent each time the airflow rate was doubled and from 2 to 3 percent approximately for each one degrees Centigrade in average temperature rise of drying air, regardless of the fan operation methods. Therefore, the average temperature rise of drying air had a little effect on drymatter loss. 9. Drymatter loss increase ranged from 50 to 78 percent approximately for each 2 percent increase in initial moisture content, in the range of 18 to 24 percent moisture. 10. The intermittent fan operation: showed about 40 to 50 percent increase in drymatter loss as compared with the continuous fan operation and the increasing rate was higher at high level of initial moisture and average temperature rise.11. Year-to-year weather conditions had a little effect on required drying time and drymatter loss.12. The equations for estimating time required to dry top layer to 16 and 1536 wet basis and drymatter loss were derived as functions of the performance factors. by the least square method.13. Minimum airflow rates based on 0.5 percent drymatter loss were estimated.Minimum airflow rates for the intermittent fan operation were approximately 1.5 to 1.8 times as much as compared with the continuous fan operation, but a few differences among year-to-year.14. Required fan horsepower and energy for the intermittent fan operation were3. 7 and 1. 5 times respectively as much as compared with the continuous fan operation.15. The continuous fan operation may be more effective than the intermittent fan operation considering overdrying, fan horsepower requirements, and energy use.16. A method for estimating the required collection area of flat-plate solar collector using average temperature rise and airflow rate was presented.

• Korean Journal of Soil Science and Fertilizer
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• v.8 no.2
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• pp.81-87
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• 1975

A pot experiment was conducted to study the effect of two methods of applying potassium fertilizer to rice. One basic application was compared with the split of same total quantity into four applications as follows: 15 days after transplanting (40%), Ear formation stage (30%), 13 days before heading (20%) and 7 days after heading (10%) Each of these two treatments was carried out on both untreated soil and soil to which wollastonite and lime material had been added. The number of ripened grains or the 1,000 grain weight was increased by application of potassium to untreated soil. However, on soil treated with lime and wollastonite only the number of total grains was increased by potassium application. In both cases, split application of the potassium was more affective than a single basic application. No significant increase in yield was obtained from a single basic application of potassium. However, split application of the same total quantity of potassium did give a significant increase in yield. A negative correlation was found between the content of $K_2O$ and that of other nutrients in the rice plant at two stages of growth. Significant negative correlation was obtained between the content of $K_2O$ and magnesium, phosphorus and nitrogen at ear formation stage, and between the content of $K_2O$ and calcium and silicate including magnesium, phosphorus and nitrogen at heading stage. This result also indicated that the depression of uptake of phosphorus and magnesium at ear formation stage and that of calcium and silicate at heading stage were decreased by potassium split application. However, the degression of uptake of nitrogen at ear formation stage and that of magnesium at heading stage were increased by potassium split application.

• Journal of The Korean Society of Grassland and Forage Science
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• v.34 no.4
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• pp.296-306
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• 2014

This study was conducted to survey and analyze the quantity of various organic wastes and to vitalize the utilization of agri-food by-products as raw materials for Total mixed ration (TMR), to improve feed cost savings and the quality of animal products. On-the-spot obstacles for animal farmers, along with legal and institutional alternatives are presented. The results are as follows. First, organic wastes in Korea are managed by the Allbaro system created in the Wastes Control Act, which processes 10,488 tons of cooking oil waste, 832,493 tons of animal and plant residues, 5,740 tons of animal carcasses, 1,171,892 tons of animal residues, and 2,172,415 tons of plant residues including 12,905 tons of rice hull and bran, for a total of 4,205,931 tons. Raw materials for TMR, namely rice hulls and bran as well as plant residues, accounted for 51.7% of the total national organic waste. The top 10 municipalities process 76~100% of all organic wastes and a supply management system is needed for the waste. Second, the 10 major agri-food by-products used as raw materials for TMR are bean curd by-product, rice bran, oil-cake, brewers dried grain, Distiller's Dried Grains with Solubles (DDGS), barley bran, soy sauce by-product, citrus fruit by-product, mushroom by-product and other food by-product (bread, noodles, snacks, etc.). Third, the biggest difficulties in using agri-food by-products are legal obstacles. Because agri-food by-products are regulated as industrial wastes by the Waste Control Act, animal farmers that wish to use them have legal reporting obligations including the installation of recycling facilities. To enable the use of agri-food by-products as raw materials for TMR, waste management system improvements such as 'the end of waste status' and the establishment of more than 10 public distribution centers nationwide are deemed essential.

• The Journal of the Korea Contents Association
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• v.16 no.5
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• pp.488-496
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• 2016

A survey of the satisfaction of school meals and food preferences was conducted with an objective to enhance the quality of food service. The study conducted a survey for 292 middle school students (152 boys and 140 girls), who were either in $1^{st}$ or $2^{nd}$ year. According to the general information, the number of $1^{st}$ and $2^{nd}$ year students was 134 and 158, respectively. Usually, the mother (92.8%) prepared meal the most, followed in order by the grandmother (5.8%) and father (1.4%). The top priorities of choosing food were taste (82.9%), good for health (6.5%), nutritional value (4.5%), and flavor (3.1%). The satisfaction was investigated using a 5 point scale. The satisfaction of taste was rice ($3.99{\pm}0.74$), side dishes ($3.99{\pm}0.65$), soup ($3.61{\pm}0.86$), kimchi ($3.54{\pm}1.12$). The satisfaction of quantity was rice ($3.88{\pm}0.83$), soup ($3.87{\pm}0.79$), kimchi ($3.80{\pm}0.89$), and side dishes ($3.71{\pm}0.93$). The satisfaction of diversity was side dishes ($4.09{\pm}0.67$), rice ($4.01{\pm}0.77$), soup ($4.01{\pm}0.64$), kimchi ($3.84{\pm}0.86$). For food preferences, the noodle was ranked highest while vegetables showed the lowest. Overall, support will be needed to develop diverse menus for students. This study suggests the need for active nutrition education for establishing proper eating habits.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.25 no.2
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• pp.6-14
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• 1980

One of the physiological disease, sudden wiliting of Yushin variety suggested that low sunlight, excessive nitrogen application, and highly reduced soil condions either singly or combined, might be possible causes of the disorder. Some visual symptom of sudden wilting are discoloration of leaves, development of nodal roots above the soil surface, total root rot, and lodging. Those observations led to the hypothesis that suffocation of root tissues was a direct cause of the wilting. The oxygen transport characteristics of Yushin, IR262 and Tongil were examined by two methods. First, Soil-cultured plants of the three varieties were subjected to paraffin treatment to decrease the oxygen supply from the air to root tissues through the soil-water system, liquid paraffin was applied to the water surface in the pots at panicle formation stage. In this experiment, sudden wilting was observed of Yushin and IR262 at about a week after the treatment, but Tongil remained green and healthy. Wilting-resistant variety Tongil had higher oxygen release, whereas the susceptible Yushin and IR262 had lower oxygen release. Second, the number and size of the air spaces in each internode were investigated in the 5th internode from the top, all three varieties have a similar number of air spaces, although the air spaces of Thongil were larger. In the 4th internode, Tongil had plenty air spaces, Yushin and one of the Yushin's parents IR262 had scanty or none. The observations indicated that the ability of Yushin and IR262 for oxygen transport is very limited compared with that of Tongil. The limited oxygen supply due to poor development of air space in internode of rice plants may cause suffocation of root tissues, weaken metabolic activity of the tissues, and induce root rot, subsequently inducing sudden wilting and lodging under unfavorable weather, soil and cultural conditions.

• Food Science of Animal Resources
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• v.30 no.1
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• pp.141-147
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• 2010

This study evaluated the antimicrobial effects of retort process and gamma irradiation on reduction of total bacterial populations in spicy chicken sauce, which is served on top of the steamed rice. Commercial spicy chicken sauce was treated with retort and gamma ray at 0, 1, 3, 5, and 10 kGy. Total aerobic bacterial populations were then enumerated on plate count agar and isolated bacteria from the test samples were identified using PCR analysis. Moreover, gamma ray sensitivity of identified bacteria was evaluated by $D_{10}$ values, and genotoxicity of gamma-irradiated samples was examined. Gamma irradiation at 3 kGy reduced total aerobic bacterial cell counts in spicy chicken sauce below detection limit, but total aerobic bacterial cell counts in test samples treated with retort were 2.1 log CFU/g. Identified bacteria from the samples were Bacillus subtilis, B. amyloiquefaciense, and B. pumils, and the $D_{10}$ values for B. subtilis and B. cereus were 0.39 ($R^2\;=\;0.921$) and 0.28 log CFU/g ($R^2\;=\;0.904$), respectively. The SOS chromotest showed that the gamma-irradiated spicy chicken sauce did not cause mutagenicity. These results indicate that gamma irradiation of spicy chicken sauce could be useful in ensuring microbial safety.

• The Korean Journal of Pesticide Science
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• v.5 no.4
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• pp.40-44
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• 2001

Pesticide actual usage in fruit crop cultivation was surveyed, and usage trends of individual pesticides were evaluated to provide data for the development of indicators of environmental impact. The amount of pesticide used for fruit crops indicated the order of fungicide>insecticide>herbicide unlike the case of paddy rice. The fungicide rate of total usage was 72% in apple cultivation. Top ranking fungicides used on fruits were Mancozeb, Propineb, Thiophanate-methyl and the main insecticides were Mancozeb, Propineb, Thiophanate-methyl. The usuage by formulation types showed the order of WP>EC>SL>SC>SP>WG. Pesticide usage (a.i.) per hectare by different fruits was citrus 48.6kg, apple 27.1kg, pear 18.6kg, persimmon 17.5kg, peach 11.3kg and grape 9.2kg. Comparison of pesticide usage (a.i.,kg/ha) in some fruit crops between Korea and USA indicated that more pesticides were used for citrus, pear and peach in USA than Korea while more pesticides were used in Korea than USA for apple.